1. Technical Field
This invention relates to blood vessel cannulation devices and is particularly directed to automatic means for catheter placement within blood vessels.
2. Background Art
Cannulating blood vessels is a common procedure in patient care, in order to administer fluids, drugs, blood or blood products. Heretofore, there have been two basic types of catheter for accomplishing cannulation. In one instance, the needle is within the catheter; while in the other instance, the catheter is within the needle. In both cases, the needle serves to penetrate the skin and the wall of the blood vessel and, once the blood vessel has been entered, the catheter is advanced manually until an adequate position is reached. Unfortunately, such manual catheter placement involves both of the operator's hands; one for stabilization of the needle, and the other for advancement of the catheter. Furthermore, manual catheter placement is an extremely delicate procedure which can be performed only by specially trained and highly skilled medical personnel and, even then, placement failure is not uncommon, due to such factors as failure to recognize penetration of the blood vessel, sequence delays, disruption of the continuity of the blood vessel, patient anatomical variability, etc.
A search in the United States Patent Office has revealed the following references:
______________________________________ U.S. Pat. No. INVENTOR ISSUED ______________________________________ 4,767,407 S. J. Foran Aug. 30, 1988 4,904,240 R. L. Hoover Feb. 27, 1990 4,944,728 M. W. Carrell et al Jul. 31, 1990 4,966,589 J. M. Kaufman Oct. 30, 1990 ______________________________________
Each of these references requires manual advancement of the catheter and, hence, is subject to the disadvantages discussed above. Thus, none of the prior art catheter placement devices has been entirely satisfactory.